The purpose of the invention is improvements to plastic bottles having reinforcing means, and which are obtained by blow-molding a plastic blank, either by heat conditioning then blow-molding, or drawing and blow-molding, previously injected preforms, or by extrusion then blow-molding of a parison. It applies most particularly, although not exclusively, to bottles intended to contain gasified beverages, such as carbonated or gaseous beverages.
One known disadvantage of bottles or other containers made of plastic is their propensity to being crushed when held in the hand, primarily after they are opened, causing the contents to be sprayed, especially when they are liquid. This phenomenon is all the more prevalent with thin-walled bottles. The current trend is to reduce the weight of bottles and thus the quantity of material of which they are composed, that is, in order to obtain a bottle of given volume and dimensions, lighter and lighter blanks (preforms or parisons) are being used today.
When the bottles are closed and they contain a non-sparkling product (liquid or other), the risk of crushing when taken in hand is nearly nil; it can, however, undergo a slight deformation that is rarely irreversible. Indeed, in this case the presence of the closing device prevents the variation of the internal volume when it is picked up. At most, a deformation of the wall at constant volume occurs.
When the bottles are closed and they contain a gaseous or gasified product, then not only the risks of crushing related to being taken in hand, but also the risks of deformation when grasped, become nearly nil. Indeed, in this case the gas pressure inside the bottle exerts a force on the inner surface of the wall that resists both the variation in internal volume and the force exerted by the user to hold it, such that the higher the internal pressure the less deformation of the wall.
When it is opened, however, the risk of crushing is all the greater because the user is least expecting it. This is usually the case when the bottle is filled with gaseous or gasified contents. In effect, in this case the user tends to be less careful because when the bottle is closed, the user feels that it is very rigid.
These disadvantages have been partially remedied by making bottles having reinforcing ridges on the periphery of their body. However, this solution is only somewhat satisfactory from a mechanical point of view for non-sparkling contents.
Indeed, 1) when the ridges are large enough to prevent crushing when the bottles are opened, such bottles, when closed and filled with gaseous or gasified contents, tend to be deformed from the effect of the internal pressure by unfolding, even creep at the ridges; or 2) when the ridges are small in size to prevent appreciable deformation due to the internal pressure when the bottles are closed, in this case, upon opening, the ridges are usually not rigid enough to prevent crushing.
Moreover, this solution runs counter to making the bottles lighter, because enough material must be provided to enable to ridges to be made.
U.S. Pat. No. 5,803,290 reveals a bottle having a groove made around the body of the bottle, said groove having a lower part for connection to the body, a central part, and an upper part for connection to the body. By virtue of its profile, the groove provides not a little reinforcement when the bottle is open. However, the structure of the groove is such that there are areas that are susceptible to creep or deformation, particularly from the effect of the internal pressure, when the bottle is closed and filled with a gaseous or gasified product.
A purpose of the invention is to remedy these disadvantages.
According to the invention, a plastic bottle having a body that is cylindrical as generated by rotation, between the bottom of the bottle and the shoulder area, and provided with reinforcing means composed of a groove made around the body of the bottle, said groove havingxe2x80x94from bottom to topxe2x80x94a lower part for connection to the body, a central part, and an upper part for connection to the body, each of these parts having a peripheral profile of a constant simple curve, the central part having a peripheral profile with a concavity turned toward the outside of the bottle, the upper and lower parts each having a profile with a concavity turned toward the inside of the bottle, characterized in that the lower part, the central part and the upper part of the groove each have a constant curvature, thus a segmental profile, and in that the upper and lower parts are each connected tangentially to the body and to the central part.
In point of fact, it is the combined profile of the three parts of the groove that makes is possible on the one hand to provide effective protection against crushing upon opening, and on the other hand to prevent the reinforcing means from becoming deformed under the effect of internal pressure; indeed, on the one hand the presence of curved areas tangentially connected to adjacent areas, and on the other hand the existence of peripheral profiles with constant curvature, that is, segmental profiles, means that in the reinforcing means there are no folds or areas susceptible to creep or deformation particularly under the effect of the internal pressure, when the bottle is closed and filled with a gaseous or gasified product, or under the effect of an external force when the bottle is open.
According to another characteristic, the dimensions of the reinforcing means are such that in addition to their reinforcing function, they offer a grip function for the bottle, that is, the user can easily grip the bottle at the groove. For that purpose, the total height of these reinforcing means is preferably between 60 mm and 100 mm, which allows a hand to be positioned therein.
According to another characteristic, the reinforcing means are situated in the upper part of the body. Preferably, then, these means are arranged at or slightly above the center of gravity of the bottle, which further promotes its grip, particularly while they make it possible to provide the above-mentioned gripping function of the bottle. Secondarily, this makes it possible to have, at the lower part of the bottle, an area where a label can be placed.
According to another characteristic, the diameter at the bottom of the groove, that is, at the bottom of the central part, has a value of between 50% and 80% of the maximum diameter of the rest of the body of the bottle, preferably between 60% and 70%. The groove thus has a significant depth that improves the reinforcing effect even more.
According to another characteristic, the upper part and/or the lower part of the groove have a curvature with an average radius of curvature the value of which is between 35% and 55% of the radius of the body of the bottle, and preferably on the order of 40%.
According to another characteristic, the lower part and the upper part of the groove have an identical curvature.